1. Field of the Invention
The present invention relates to an anti-entrapment system provided with a capacitance sensor for preventing entrapment of an object.
2. Background Art
Anti-entrapment systems use various types of sensors to detect pinching of an object such as a human body part. For example, in automobiles, sensors are used for pinch sensing at electrically operated doors, windows, hatches, decks, hoods, lids, and the like.
A pinch sensor detects pinching an object by a translating device such as a window, door, sunroof, etc. In operation, the pinch sensor generates a pinch sensor signal in response to the object such as a person""s finger being pinched by a translating device such as a window as the window is closing. In response to the pinch sensor signal, a controller controls the window to reverse direction and open in order to prevent further pinching of the person""s finger. As the window is opening, the person may remove his finger from the window opening between the top edge of the window and the window liner.
Motor current sensors, infrared beam sensors, and continuous switch sensors have been used as pinch sensors in anti-entrapment systems. A problem with these types of pinch sensors is that they require a relatively large amount of pinching of the object to take place before they detect pinching of the object.
Accordingly, it is an object of the present invention to provide an anti-entrapment system having a sensor that detects a translating device pinching an object as soon as the translating device has applied a relatively small amount of pinching to the object and/or detects the presence of the object within an opening which may be closed by the translating device in order to prevent any pinching of the object by the translating device.
In carrying out the above object and other objects, the present invention provides an anti-entrapment system for preventing an object from being entrapped by a translating device. The system includes a capacitance sensor positioned adjacent to a translating device. The capacitance sensor has first and second flexible conductors separated by a separation distance. The first and second flexible conductors have a capacitance dependent on the separation distance. The capacitance sensor further has a compressible dielectric element interposed between the first and second flexible conductors.
The capacitance of the first and second flexible conductors changes in response to the separation distance changing as a result of the dielectric element compressing in response to a first object touching the capacitance sensor. The capacitance of the first and second flexible conductors changes in response to a second conductive object coming into proximity with at least one of the first and second flexible conductors. A controller controls the translating device as a function of the capacitance of the first and second flexible conductors in order to prevent the translating device from entrapping either of the first object or the second conductive object.
The first flexible conductors may be a center core with the second flexible conductor coaxially surrounding the dielectric element and the first flexible conductor. In this case, the first flexible conductor may be electrically grounded.
An elastomer overcoat which may be semi-rigid may surround the second flexible conductor. The dielectric element may be a semi-rigid elastomer, air, a cell foam, and the like. At least one of the first and second flexible conductors may include a braided metal wire.
The translating device may be an automobile window. In this case, the capacitance sensor may be positioned on a window body panel which receives the automobile window when the automobile window is in a fully closed position. The capacitance sensor may be formed integral with an automobile weather strip which receives the automobile window when the automobile window is in a fully closed position.
The translating device is an automobile sliding-door, an automobile sunroof, an automobile deck lid, an automobile hatch, an automobile tonneau cover, and the like. The translating device may also be a pair of doors, a pair of elevator doors, a garage door. The translating device may also be a movable press mechanism.
The controller, which may include a microprocessor, may be operable for generating an offset signal to bias the capacitance between the first and second flexible conductors. The controller may also be operable for executing filtering software to monitor the capacitance between the first and second flexible conductors. The controller may be further operable for executing an adaptive threshold detection algorithm to monitor the capacitance between the first and second flexible conductors.
Further, in carrying out the above object and other objects, the present invention provides a second anti-entrapment system for preventing an object from being entrapped by a translating device. The second anti-entrapment system includes a capacitance sensor positioned adjacent to a translating device. The capacitance sensor has first, second, and third flexible conductors. The conductor coaxially surrounds the second conductor with a first compressible dielectric element interposed therebetween. The second conductor coaxially surrounds the first conductor with a second compressible dielectric element interposed therebetween. The first and second conductors are separated by a separation distance. The second conductor is electrically grounded.
The first and second conductors have a capacitance dependent on the separation distance. The capacitance of the first and second conductors changes in response to the separation distance changing as a result of the second dielectric element compressing in response to a first object touching the capacitance sensor. The second and third conductors have a capacitance dependent on the proximity of a second conductive object with the third conductor. The capacitance of the second and third conductors changes in response to the second conductive object coming into proximity with the third conductor. A controller controls the translating device as a function of the capacitance of the first and second conductors and the capacitance of the second and third conductors in order to prevent the translating device from entrapping either of the first object or the second conductive object.
Also, in carrying out the above object and other objects, the present invention provides a third anti-entrapment system for preventing an object from being trapped by a translating device. The third anti-entrapment system includes a capacitance sensor positioned adjacent to a translating device. The capacitance sensor has a capacitance pinch sensor and a capacitance proximity sensor positioned side-by-side and both being encased by a single elastomer outer jacket.
The capacitance pinch sensor includes first and second flexible conductors and a first compressible dielectric element interposed therebetween. The second conductor coaxially surrounds the first dielectric element and the first conductor such that the first and second conductors are separated by a separation distance. The second conductor is electrically grounded. The first and second conductors have a first capacitance dependent on the separation distance. The first capacitance changes in response to the separation distance changing as a result of the dielectric element compressing in response to a first object touching the capacitance pinch sensor.
The capacitance proximity sensor includes third and fourth conductors and a second compressible dielectric element interposed therebetween. The fourth conductor coaxially surrounds the second dielectric element and the third conductor. The third conductor is electrically grounded. The third and fourth conductors have a second capacitance which changes in response to a second conductive object coming into proximity with the fourth conductor.
A controller controls the translating device as a function of the first and second capacitances in order to prevent the translating device from entrapping either of the first object or the second conductive object.
Still further, in carrying out the above object and other objects, the present invention provides a fourth anti-entrapment system for preventing an object from being entrapped by a translating device. The fourth anti-entrapment system includes a capacitance sensor positioned adjacent to a translating device. The capacitance sensor includes an elastomer outer jacket having an interior. The capacitance sensor further includes a spanner held at each end by the outer jacket within the interior of the outer jacket. The spanner holds a first flexible conductor within the interior of the outer jacket and the outer jacket encases a second flexible conductor such that the first and second conductors are separated from one another by a separation distance. The first and second conductors have a capacitance dependent on the separation distance. The capacitance sensor further has a compressible dielectric element within the interior of the outer jacket. The capacitance of the first and second conductors changes in response to the separation distance changing as a result of the dielectric element compressing in response to a first object touching the outer jacket. The capacitance of the first and second conductors changes in response to a second conductive object coming into proximity with at least one of the first and second conductors. A controller controls the translating device as a function of the capacitance of the first and second conductors in order to prevent the translating device from entrapping either of the first object or the second conductive object.
The spanner may include first and second portions. The first spanner portion being a conductive flexible elastomer and the second spanner portion being a non-conductive flexible material. The first spanner portion holds the first conductor within the interior of the outer jacket. The second spanner portion is held at each end to the outer jacket.
Yet further, in carrying out the above object and other objects, the present invention provides a fifth anti-entrapment system for preventing an object from being entrapped by a translating device. The fifth anti-entrapment system includes a capacitance sensor positioned adjacent to a translating device. The capacitance sensor has a flexible conductor separated from a metal frame by a separation distance. The conductor has a capacitance dependent on the separation distance. The capacitance sensor further has a compressible non-conductive elastomer encasing the first conductor and resting on the metal frame. The capacitance of the conductor changes in response to the separation distance changing as a result of the compressible non-conductive elastomer compressing in response to a first object touching the first conductor. The capacitance of the conductor changes in response to a second conductive object coming into proximity with the conductor. A controller controls the translating device as a function of the capacitance of the conductor in order to prevent the translating device from entrapping either of the first object or the second conductive object. The conductor may have an endless configuration.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the preferred embodiment(s) when taken in connection with the accompanying drawings.